• L. Giannessi, M.C. Carpanese, F. Ciocci, G. Dattoli, A. Dipace, A. Doria, G.P. Gallerano, E. Giovenale, G. Parisi, M. Quattromini, A. Renieri, C. Ronsivalle, E. Sabia, S. Spampinati, I.P. Spassovsky
  ENEA C.R. Frascati, Frascati (Roma)
• D. Alesini, M.E. Biagini, A. Drago, M. Ferrario, V. Fusco, A. Ghigo, B. Spataro, C. Vaccarezza, C. Vicario
  INFN/LNF, Frascati (Roma)
• M. Bougeard, B. Carre, M.-E. Couprie, D. Garzella, M. LABAT, G. Lambert, H. Merdji, P. Salieres
  CEA/Saclay, Gif-sur-Yvette
• M. Mattioli, P. Musumeci, M. Petrarca
  Universita di Roma I La Sapienza, Roma
• M.  Migliorati, L. Palumbo
  Rome University La Sapienza, Roma
• M. Nisoli, S. Stagira, S. de Silvestri
  Politecnico/Milano, Milano
• L. P. Poletto, G. T. Tondello
  Univ. degli Studi di Padova, Padova

Funding: Work supported by the EU Commission in the sixth framework programme, contract no. 011935 – EUROFEL.

Sources based on high order harmonics generated in gas with high power Ti:Sa lasers pulses represent promising candidates as seed for FEL amplifiers for several reasons, as spatial and temporal coherence, wavelength tunability and spectral range, which extends down to the 10(-9)m wavelength scale. This communication is devoted to the description of a research work plan that will be implemented at the SPARC FEL facility in the framework of the EUROFEL programme. The main goal of the collaboration is to study and test the amplification and the FEL harmonic generation process of an input seed signal obtained as higher order harmonics generated both in crystal (400nm and 266 nm) and in gas (266nm, 160nm, 114nm) from a high intensity Ti:Sa laser pulse.

• G. Parisi, F. Ciocci, G. Dattoli, L. Giannessi, G. K. V. Voykov
  ENEA C.R. Frascati, Frascati (Roma)

In the framework of the SPARC FEL experiment, a 14-m long undulator divided into six sections is presently under construction (by ACCEL Instruments GmbH). In order to correct the phase difference between the electron beam and the radiation, a tunable device will be inserted at the end of each of the six sections of the undulator. In this paper a preliminary design of this device, performed with RADIA code, is proposed,. The phase shifter consists of two groups of a few permanent magnets, arranged as in the main undulator in a variable gap magnet assembly. Adjusting the gap allows to correct the electron-radiation phase difference. Results from beam dynamics simulation, performed with GENESIS code, show the impact of the phase shifter on the characteristics of the output laser field.

• F. Ciocci, G. Dattoli, L. Giannessi
  ENEA C.R. Frascati, Frascati (Roma)
• S. Biedron, S.V. Milton
  ANL, Argonne, Illinois
• H. Freund
  SAIC, McLean

We study the spectral details of planar bi-harmonic undulators and show that they have quite interesting properties. They can indeed be exploited to enhance or suppress harmonics and can be exploited in high gain segmented FEL devices to make more efficient the mechanisms of harmonic generation. We also show that the formalism we develop can be extended to the multi-component case and can usefully be exploited to study undulator magnetization errors.

• L. Palumbo
  Rome University La Sapienza, Roma
• D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M.  Migliorati, A. Mostacci, L. Pellegrino, M.A. Preger, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario
  INFN/LNF, Frascati (Roma)
• F. Alessandria, A. Bacci
  INFN/LASA, Segrate (MI)
• F. Broggi, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, M. Mauri, V. Petrillo, M. Rome, L. Serafini
  INFN-Milano, Milano
• L. Catani, E. Chiadroni, A. Cianchi, C. Schaerf
  INFN-Roma II, Roma
• F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P.L. Ottaviani, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle
  ENEA C.R. Frascati, Frascati (Roma)
• P. Emma
  SLAC, Menlo Park, California
• M. Mattioli
  Universita di Roma I La Sapienza, Roma
• P. Musumeci
  INFN-Roma, Roma
• S. Reiche, J.B. Rosenzweig
  UCLA, Los Angeles, California

The first phase of the SPARX project, now funded by MIUR (Research Department of Italian Government), is an R&D activity focused on developing techniques and critical components for future X-ray FEL facilities. This project is the natural extension of the activities under development within the ongoing SPARC collaboration. The aim is the generation of electron beams characterized by an ultra-high peak brightness with a linear accelerator based on the upgrade of the existing Frascati 800 MeV LINAC and to drive a single pass FEL experiment in the range of 3-5 nm, both in SASE and SEEDED FEL configurations, exploiting the use of superconducting and exotic undulator sections. In this paper we discuss the present status of the collaboration.